Manufacture of pulp articles



J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPLICATION F'ILED AUG-15, 1916.

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MANUFACTURE OF PULP ARTICLES.

APPLICATION FILED AUGJE. (EH6.

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J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPucATlon FILED AUGJS, 1916. 1,367,096, Patented FBI). 1, 1921.

4 SHEETS-SHEET 3- ATTORNEYS J. H. RIVERS.

MANUFACTURE OF PULP ARTICLES.

APPLICATION FILED AUGJS. I916. 1,367,096. Patented Feb. 1,1921.

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IMVEIVTOR lull ' ATTORNEY-5' A... hmx MN WITNESSES:

UNITED STATES PATENT OFFICE.

JULIAN H. RIVERS, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO UNIVERSALFIBRE COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

MANUFACTURE OF PULP ARTICLES.

Application filed August 15, 1916.

To all whom it may concern Be it known that I, JULIAN H. Rivers, acitizen of the United States and a resident of Jersey City, county ofHudson, State of New Jersey, have invented certain new and usefulImprovements in the Manufacture of Pulp Articles, of which the followng, taken in connection with the accompanying drawings, is aspecification. I

My invention relates to the manufacture of articles from pulp, such asfor instance paper pulp and includes as its objects a method offormation which insures a proper distribution of the suspended particlescomprising the pulp wherebyan article of superior structuralcharacteristics is produced, as Well as mechanism of suitableconstruction to render the carrying out of such method easy andexpeditious from a commercially practical standpoint. Other objects willbe specifically pointed outor will otherwise appear in the followingdescription of the invention in which the mechaiiism shown in theaccompanying drawings will be availed of for illustrative purposes, itbeing, of course, understood that such other mechanism than that shownmay be employed in the carrying out of my invention as may fall withinthe inventive scope and spirit set forth in the appended claims.

In said drawings Figure 1 is a side elevation of the mechanism which maybe employed in accordance-with my invention for the production of hollowarticles such as kegs, cans or similar contalners, the mold and certainother parts being shown in vertical section.

Fig. 2 is a plan view of the mold and associated parts of suchmechanism, the side walls of the mold being in open position and certainparts being in horizontal section along substantially the line 22 ofFig. 1.

Fig. 3 is a front elevation of the mold and its supporting andassociated elements.

Fig. 4. is an enlarged horizontal section of the mold on substantiallythe line l4 of Fi 5.

Fig. 5 is an enlarged vertical section of the mold, the top, side andbottom walls thereof being in separated relation.

Fig. 6 is an enlarged vertical section of cooperating portions of theside and bottom walls of the mold. I

Fig. 7 is a detail, elevation showing the Specification of LettersPatent.

detail of the construction Patented Feb. 1, 1921. Serial No. 114,944.

latch mechanism for holding the separable parts of the mold in closedposition.

Fig. 8 is a plan view, with parts in sect on, of a modified moldingmechanism particularly adapted for the production of fiat pulp boards.

Fig. is a side elevation of such modified mechanism, parts being insection.

F g. 10 is a front view thereof.

Fig. 11 is a diagrammatic representation showing the principal parts ofsuch modified mechanism in vertical section, and

Fig. 12 is a vertical section illustrating a thereof.

In connection with either of the two molding mechanisms shown, there ispreferably employed a pulp container 13 provided with an agitator 14mounted on the vertical, power-driven shaft 15 and a pulp, inlet 16 anda pulp outlet 17, the latter being furnished with a suitable valve, suchasthe manually operable slide valve18. Connecting with the containeroutlet 17 below the valve 18 thereof are a plurality of moldingmechanism inlet pipes 19, two only of which are shown in Fig. 1, oneleading to the molding device of Fig. 1 and the other being broken offas shown, but being in practice connected, if desired, with any suitablemolding device, such as a device of the kind shown in Fig. 1 or a deviceof the kind shown in Figs. 8 to 12 inclusive. A valved drain pipe 20 maybe connected with the container outlet 17.

The molding mechanism for hollow articles comprises, generally speaking,separable, perforated mold walls, means for separating them and bringingthem together, supporting means and means for controllably connectingthe mold with the source of pulp. The mold prop r may b regarded asconsisting of the upper wall section'2l, the side wall section 22 andthe lower wall or bottom section 23, the latter being secured to andsupported upon the studs 24 which rest -upon the bottom of chamber 25.The shell of this chamber is supported by legs or frame 27, and in turnsupports table 26. The bottom section 23 is provided with an annularflange 28 projecting under the table 26 and limiting. the movementofsaid section upwardly from its position upon the studs 24. In order toinsure a liquid-tight joint between the bottom beyond the said joint andthe bottom of said chamber connects with the molding mechanism inletpipe 19 through the intermediary of a pipe section 30 provided with avalve 31. The-pipes 30 and 19 are also connected -with a discharge pipe31 provided with a valve 32.

The chamber 25 is connected with the 1nterior of the mold through a moldentrance pipe 33 extending vertically through the center of the bottomsection 23, and is provided with a horizontal baflle 34 which extendsacross, though spaced from, the discharge end of pipe 30 so as toprevent the pulp admitted to the chamber from spurting into the moldthrough the pipe 33. The side of the chamber is connected by the pipe 35with the valved air pressure pipe 36, the upper end of which leads tothe upper portion of tank 13 and to a source of compressedair; and withthe valved superheated steam pipe 37.

The mold shown comprises three sections provided with foraminated wallsto retain the deposited pulp and passages therebehind to allow of theescape of the water or other medium in which the pulp is suspended.These walls and passages may be of any known construction, such forexample as that shown and described in my Patent No. 1,174,447, datedMarch 7, 1916. In the accompanying drawings the surface for receivingthe pulp is formed by the fabric 38 backed by the perforated metal sheet39 set against the supporting ribs 40, (see Figs. 4. 5 and 6) the latterbeing arranged in any suitable manner to support the filtering surfacefirmly and at the same time to permit of ready drainage. The spacesbetween these ribs in the bottom section are connected with the drainagepipe 41 provided with the check valve 42 (Fig. 1) for allowing outwardflow only.v The drainage spaces of the top section are connected withthe valved and branched central drainage pipe 43, while those of thecentral section are so constructed as to be in communication with thoseof the top and bottom sections.

When in closed relation in which the mold parts form a hollow mold withtop, bottom and cylindrical sides, the central mold section rests uponand fits into an annular rabbet in the bottom section. and the topsection rests upon the central section, being provided with a rabbetwhich insures a suitable fit between said sections. The central sectionis preferably made of three segments two of which are hinged to thethird by pintles 44, and held closed by the latch 45.

For separating the mold sections and holding them in separated relationa fluid pressure motor 46 is provided. This motor is secured to theunderside of the table 26, its piston rod 47 projecting through saidtable and secured thereabove to the block 48 slidable vertically in theguide 49. Air or water or other fluid under pressure is supplied to themotor cylinder through the pipe 50 provided with a valve 51 soconstructed as'to admit fluid into said cylinder in one position of thevalve and to allow drainage therefrom into the waste pipe 52 in anotherposition thereof. The block 48 is connected by the forked connecting rod53 with the levers 54 at an intermediate point thereof, one end of saidlevers being pivoted at 55 to a stationary upright bracket 56 and theother ends thereof being connected with the top section of the moldthrough the links 57 and the I-beams 58 secured to said links and tosaid mold section. The ends of the I-beam structure are guided upon thevertical columns 59 secured at their lower ends to the table 26.

The connecting rod 53 is provided with a pendant rod 60 pivoted at itsupper end to the lever near the upper end thereof, the lower end of saidpendant rod passing through the eye 61 secured to the central moldsection. The extreme lower end of the rod is threaded to accommodate anadjustable nut 62 of such size as not to pass through the eye.

Upon admission of fluid under pressure to the motor 46 through thepipe50, the piston rod 47 and with it the guide block 48 and theconnecting rod 53 is caused to rise. The movement of the connecting rodcauses the lever 54 to rotate upon its pivot and thus move upwardly thelinks 57, the I-beam structure 58 and the upper section of the molduntil the latter has been swung free of the central mold section. Thismovement also raises the rod 60, which. however, at first slides freelythrough the eye 61. Suflicient further movement of these parts raisesthe nut 62 upwardly until it raises the eye and with it the central moldsection, the latter moving upward upon pintles 44 which are carried bybracket 63 fixed to bracket 56. This further movement causes the centralsection to become separated from, so as to swing clear of, the lowersection of the mold and at its limit the mold sections are in theseparated relation shown in Fig. 5 and the parts 52, 54, 57 are as shownin dotted lines in Fig. 1. In this position the central section may beunlatched and opened to the position shown in Fig. 2, and the formedpulp article A may be removed easily and without breakage.

Upon manipulation of the valve 51 to allow the cylinder contents ofmotor to drain into the pipe 52, the parts will descend by gravity tothe closed position thereof shown 1n Fig. 1. In order to retain them inthis position clutch elements 65 (see Fig. 7) are provided to engagewith the front and rear portions of the guide columns 59 which arenotched, to facilitate the clutching action. The front pair of clutchelements and the rear pair thereof are moved to effect the turning ofthe clutch elements 65 upon their lower edges which act as pivots andare supported upon the I-beam structure 58, by the lever system 67cooperating with the lever 68 ivoted at 69 upon the I-beam structure. heangle pieces 66 connect the clutch elements 65 operating upon one of thecolumns 59, to those acting upon the other column.

A spring 70 secured at one end of, this lever and at the other end tothe I-beam structure tends to pull the inner end of the lever 68 and thelever system 67 downwardly so as to throw the clutch elements inclutching relation to the guides 59. The outer end of the lever 68 isprovided with a pull chain 71 adapted to be operated by hand against thespring tension so as to release the clutch elements. The dotted lines ofFig. 7 illustrate this released position. It is, of course, obvious thatthe clutch elements must be released before the motor 46 is o erated forthe purpose of separating the mo d sections.

The modified structure shown in Figs. 8 to 12 inclusive is adapted toproduce simul taneously a plurality of flat pulp boards. (The details ofthis structure form the subject matter of claims presented in mycopfnding application, Serial No. 235,109, filed ay 17, 1918.) Itconsists of a hollow mold structure provided with flat perforated sidewalls carried upon lateral sections capable of being moved from a closedposition of the device in which the side walls cotiperate with thestationary walls to form a hollow chamber, to an open position in whichthe side walls are brought clear of the other walls, so that the pulpboards formed upon the side walls may be removed therefrom.

The apparatus is supported upon the legs 72 to which the stationarystructure consisting of the top wall 73, the end walls 74 and the bottomsection walls 75 are secured. Leading into the chamber through thebottom wall thereof is the pulp inlet pipe 76 connected below the valve77 therein with a pipe leading from a suitable supply of pulpliquor,such as for example the pipe 19 connected with the container 13. Belowthe connection with pipe 19 there is provided a discharge pipe 78equipped with a valve 79.

in Fig. 1. Above these the air and steam pigle 135 perforates the wall 75.

ach of the side sections consists of a double Wall the inner one 81 ofwhich is perforated and supported against the unperforated outer wall 82by ribs, shown schematically by the zigzag lines of Fig. 11, which formbetween them intercommunicating passages through which the pulp liquormay be led into the discharge apertures 83. These draining walls andpassages may be generally similar in construction to those of the barrelmold previously described. Behind the imperforate wall 82 is a chamberformed between said wall and the domeshaped exterior side wall 84. Theperiphery of the inner wall of each side section is provided with arabbet into which for one side section fits the lateral edges of theangle irons 85 fixedly secured to the stationary top, end and bottomwalls of the mold and for the other side section fits the edges of thelaterally floating frame 86 between which and the stationary top, endand bottom walls of the mold a liquid-tight joint is provided by aflexible connection such as the corrugated sheet metal connection 87 theperipheral edges of which are secured to said top, end and bottom wallsand the inner edges of which are secured to said floating frame, whichframe with its attached flexible gasket 87 performs the same function asthe edge of plate 23 (Fig. 1) and its flexible corrugated ring 29.

The ends of the side sections are provided with projecting pins 88 uponwhich book the lateral latch bars 89 when the mold is closed, which barsare secured to the lateral latch rods 90 which extend vertically and areconnected at their upper ends with the top latch rods 91. Secured to theunderside of these latch rods 91 are the top latches 92 the hooked endsof which coiiperate with the pins 93 carried in the brackets 94 upon thetops of the mold side sections. The lower ends of the lateral latch bars90 are provided with outwardly projecting pins which extend intosuitable terminal slots in the levers 95 (Fig. 9) the opposite ends ofwhich are fixed to the shafts 96 pivotally mounted in the bearings 97upon the stationary side walls of the bottom section 75 of the mold. Theshafts are provided with bottom latches 98 which hook upon the pins99-carried in the ears 100 projecting downwardly from the side sections.

It will be readily understood that by moving upwardly the top latch rods91 as by means of the cross-bar 101 secured thereto and the pulley orratchet lift chain 102 secured to said bar, the top latches 92 will belifted so as to become unhooked from the pins 93, and the lateral latchbars 90 will also move upwardly and with them the lateral latches 89 soas to unhook the latter from the ,pins 88. Moreover the pins on thelower ends of the lateral latch bars 90 will rock the shafts 96 throughthe intermediary of the levers 95 so as to unhook the bottom latches 98from the pins 99. The side mold sections are now free so that they canbe moved to the open position shown by dotted lines in Fig. 9 by themechanism now to be described.

At each end of the mold and secured to the stationary end walls 74thereof horizontally extending tracks 103 strengthened by the braces 104are provided. Resting upon these tracks are rollers 105 rotatablycarried upon pins secured to the blocks 106 secured to the mold sidesections; thus the side sections are each capable of being supported byrollers upon the tracks.

At the ends of the mold and supported by the legs 72 are the fluidpressure motors 107 each comprising a cylinder connected by suitablevalved connections (not shown) which may be similar to those of themotor 46 of Fig. 1, with a supply of fluid under pressure. The pistonrod 108 of each of the motors 107 is connected by links 109 with thebell crank levers 110 pivotally mounted on the shafts 111 mounted inbearings 112 on the frame 72. The upper ends of the bell crank levers110 are connected by links 113 with the pins of rollers 105.

The chambers of the side sections formed between the walls 82 and 84 areconnected with the interior of the bottom section of the mold by theconnection shown enlarged in Fig. 12. This connection comprises thefloating pipe 114 passing through an aperture formed in the side wall ofthe bottom mold section and secured thereto by the diaphragm connection115. This diaphragmv connection comprises a corrugated metallic disk theperiphery of which is secured to the interior of said side wall and thecentral portion of which, apertured for the passage of the floating pipe114, is secured to said pipe by a leak-proof joint. The portion of saidpipe which extends exteriorly of said side wall is guided Within thecollar 116 bolted to the outside of said wall and a spring 117 withinsaid collar and between said side wall and the flange 118 on the outerend of said floating pipe tends to thrust said pipe outwardly and tomaintain a close connection between the conical valve face on theextremity of said pipe and the cooperating valve face on the inner endof the angle or elbow pipe 119 the outer vertical end of which isconnected by the pipe 120 with the interior of said side sectionchamber. Straddling the collar 116 and pivoted thereto is the U-shapedsecuring member 121 provided with a cam 122 pivoted thereto and equippedwith a handle 123. It is obvious that to release the securing member itis only necessary to turn down the handle 123, whereby the cam 122becomes free of the angle pipe 119 and then move the thus freed securingmember 121 downwardly to the position shown dotted in Fig. 12.

It will be seen that when the side sections have been unlatched and thepipe connection freed as explained above, and fluid under pressure isadmitted to the motors 107, the bell crank levers 110 will be moved tothe dotted position of Fig. 9 and the side sections will move laterally,these rollers 105 rolling upon the tracks 103 and the pipe connectionelements 119 and 120 withdrawing from, the floating pipe 114 until theyhave assumed the open position shown by the dotted lines in said figure.

The process of my' invention, generally speaking, comprises admittingpulp-liquor 1nto a mold chamber from below so as to fill the chamber,maintaining it in drainage contact with the perforated mold walls untila sufiicient quantity of pulp has deposited thereon, and then removingthe remaining pulp-liquor, and, without diminution of pressure to anyconsiderable extent admitting drying fluid under pressure. (When I speakof pulpdiquor I refer to pulp suspended and freely floating in water orother fluid, having added thereto, if desired, cement, sizing materialand other substances.) Preferably the amount of water should besuflicient to allow each pulp particle to float separately, or freely,until all the particles are finally deposited in the mold.

By introducing the pulp-liquor through an openlng in or near the bottomof the mold instead of through an opening in or near the top of the moldI obtain a number of marked advantages. Any foreign matter, such as dirtand rust specks, contained in the pulp-liquor, need not be deposited inthe forming article, but has the opportunity of settling before theliquor reaches the mold, or of settling while the liquor is in the mold,and of dropping out of the opening. By thus making the article inprocess of formation the head of the operating column of pulp-liquor,instead of the foot, I also prevent microscopic fragments of pulp, whichare present in the pulp-liquor, and have very little, if any, structuralvalue, from depositing at all, as they are kept afloat by the agitationof the liquid, and are withdrawn with the liquid when the pressuremedium is admitted to the mold by means of the by-pass. I can quicklyempty the mold of pulp-liquor, and introduce my drying mediumimmediately, thus securing a uniform drying; instead of either awaiting,as heretofore, the drainage of all the pulp-liquor from the mold, orintroducing my drying medium before such drainage has been comportionsthereof. I can therefore by my new process work with hot pulp-liquor,instead of with cold pulp-liquor as was necessary heretofore, and thusgain the obvious advantage in drying, as there is no longer any dangerof a complete drying of one portion of an article before the drying ofanother portion has been hardly begun (thus causing unevenness andtension) which danger could hitherto be overcome only by using coldpulp-liquor for the purpose of retarding the drying operation.

A further important advantage of the new process is that it ispeculiarly adapted for multiple production. Any number of molds ofvarious shapes and capacities may be fed from a common supply tank, eachdrawing automatically an amount substantially in proportion to the areaof its drainage surace.

Thus, feeding from a tank containing pulp-liquor containing 1 grain ofpulp per cubic inch, and governed entirely by the time of flow allowed,I have operated simultaneously a 3 gallon can mold12 inches high having561 square inches drainage surface; and a 16 gallon barrel mold 22inches high, having 1350 square inches drainage surface; the extent ofthe two drainage surfaces being in the approximate proportion of 1 to2.4.

In seconds the can mold had a deposit of 11,771 grains, while the barrelmold had a deposit of 28,572 grains.

In seconds the can mold had a deposit of 12,427 grains, while the barrelmold had a deposit of 29,445 grains.

In each case the proportion between the deposit on the can mold and thedeposit on the barrel was approximately the same as the proportionbetween the drainage sur faces of the respective molds. Thus 111712.4=28250, as compared with 28572 actually deposited; and 12427 2A=28824as pompared with 29445 actually deposited. At the desired moment thedrying fluid may be admitted to each simultaneously whereby the fillingand drying of a number of molds of different heights may be accomplishedas a single operation. It is obvious that such a process is notpractical when the molds are fed from above, in accordance with theprior processes, because the whole contents of every mold would have tobe deposited before drying could be completed, thus producingirregularities in drying and uneven thicknesses of deposit for thevarious articles.

A special advantage of the present proc ess in connection with hollowarticles is that all structural weaknesses are eliminated such aspitting caused by the dripping of drying fluid condensed within themeasuring chamber above the mold chamber and falling'upon the interiorbottom of the article.

In carrying out my process with the aid of" the hollow article apparatusillustrated, a charge of suitable pulp, suspended preferably in water,is first admitted through the pulp inlet 16 into the container 13 andkept in homogeneous condition by the operation of the agitator 14. Whenit is deslred to flow pulp from this container into the mold shown or aplurality of molds of that or any other type the valve 18 is opened andthe pulp-liquor allowed to flow by gravity through the molding mechanisminlet pipes 19. This flow may be aided by admittlng air pressure intothe top portion of the container through the air pressure pipe 36, thevalves at the lower ends of the air pressure pipe 36 and the superheatedsteam pipe 37,

eing of course, closed. The p'ulpl1quor is thus caused to enter and flowupward in the pipe section 30, (the valve 31 being open and the valve 32in the discharge pipe 31 being closed) and then to enter the chamber 25from which it rises through the mold entrance pipe 33 and fills the moldcavity. Baille 34 revents spurting or splashing. The pulp-liquorimmediately starts to drain through the fabric 38 and perforated metalsheet 39 and after passing through the spaces between the ribs 40escapes through the liquor drainage pipes 41 and 43.

After the article A has formed in this way to a desired thickness thevalve 18 is closed and the drainage pipe valve 32 opened andsimultaneously the drying medium valve is opened to admit such fluidunder pressure into the mold through the pipe 35, chamber 25 and moldentrance pipe 33. Thus the drying fluid is admitted without sufficientloss of pressure in the mold to affect the structural density of thearticle A.

I prefer to admit, as such drying fluid, first compressed air by openingthe valve in the lower end of pipe 36 and then closing said valve and atthe same time opening the valve in the lower end of pipe 37, admittingsuperheated steam as the final drying agent. In this way there is noloss of the drying heat of the steam due to condensation upon meetingwith the pulp-liquor still unclischarged from the mold, the pipe 33 andthe chamber 25. Of course, steam or superheated steam may be used alone,but preferably air is first admitted, as explained, and caused to actuntil all of the pulp-liquor has been drained, at which point of timethe slidevalve 32 is closed.

\Vhen the article A has become sufficiently dried by the superheatedsteam, which causes the evaporation of interstitial water and theremoval of such water through the draina i es 41 and 43, the dr 'ngfluid pipe vgl v is closed and the mold is read to open. This operationis accomplishe by pulling down the chain 71 to release the clutchelements 65 and opening the valve 51 to admit fluid under pressure tothe motor 46, resulting in the separation of the mold sections, ashereinbefore explained, to the position shown in Fig. 5. By unlatchmgthe element 45 the central mold section may 1tself be swung open, aswill be readily understood, to the position shown in Fig. 2 and thefinished article A can easily be removed. The mold is then closed for asecond forming operation in the manner previously described, the clutchelements 65 acting automatically to maintain the sections in closedposition.

In the operation of the modified molding device for the production offlat pulp boards the ulp is caused to flow into the inlet pipe 19 Fig.10) in the manner previously described. From this pipe it enters thebottom mold section through the pipe 7 6, the valve 77 being open andthe valve 79 in the discharge pipe 78 being closed, and encounters thesplash-preventing baflles 80, passing by which it enters and fills themold cavity and begins to deposit upon the reticulated walls 81, theulp-liquor draining through them and disc arging through the pipe 83.When a sufiicient deposit has formed, drying fluid is introduced throughthe by-pass p pe in the manner described for the hollow arti- 'clemolding apparatus, the valve 18 being closed, as before,and the drainagepipe valve 7 9 being opened and later closed as described for thecorresponding valve 32.

When the drying operation is completed,

the drying fluid pipe is closed and the device is ready for opening toremove the formed boards adhering to the walls 81. This openingoperation is accomplished by pulling upwardly the lift chain 102 tounhook the top latches 92, the lateral latches 89 and the bottom latches98 from their associated pins secured to the mold sections, in themanner already described, and then admitting fluid under pressure intothe motors 107. The piston rods 108 of these motors are thus caused tomove upwardly to produce a rotation, through the connecting links 109,of the bell crank levers 110 upon their pivots 111, the upper ends ofsaid levers 110 operating through the links 113 to move laterally thepins of the rollers 105 and the mold side sections secured to said pins,In such lateral movement the bottom portions of the side sections areswung outwardly from the stationary parts of the device, the securingmembers 121 being of course first released by operating the handle 123as above described, the top portions are swung downwardly and thecentral sections move horizontally outward being carried by their1,se7,ooo I rollers 105 which run upon the tracks 103. The outermost, oropen, position of these side sections is shown by dotted lines in Fig.9. In this position the pulp boards may be re moved in any convementway. It is obvious that to return these sections to closed position, thefluid may be drained from the motors 107 and the side sections swungback into place, and the securing members 121 locked by hand, afterwhich the several latches may be hooked to the appropriate pintlesthereon by lowering the pull chain 102.

Both the hollow article mold and the flat board mold illustrated havebeen described as being constructed with differential pressure mechanismwhereby the greater the pressure in the mold the greater will be thetightness of its joints. The operation of this special construction isas follows: In the case of the hollow article mold the lower section 23thereof normally rests upon the studs 21 but is capable of movingupwardly slightly to the limiting position in which the annular flange23 comes against the under side of the table 26. When the mold is inclosed position, the bottom section is supported upon the studs 24. Assoon as pressure fluid is admitted there is a tendency for such fluid toleak out through the horizontal joints between the central mold sectionand the top and bottom mold sections; but there is a greater tendencyfor the bottom section to move upwardly against the central section andboth of said sections to move upwardly against the immovable top sectionso as to close these joints against leakage, this movement tendencybeing due to the fact that the area of the bottom section exposed to theinterior of the chamber 25 is greater than the area of either the top orbottom sections exposed to the interior of the mold. The result is thatleakage is practically impossible; and the rabbeted fitting of thevarious mold sections, furthermore, holds the cent ral section fromswinging open even though it be not provided with the latch mechanism4-5.

In the flat board mold one of the side sections forms a rabbeted jointwith a floating frame 86 (Fig. 11) movable slightly laterally on accountof its flexible connection 87 with the stationary walls of the moldcavity. Any tendency of the pressure fluid to tree this joint and allowleakage therethrough is overcome by a greater tendency to tighten thejoint, this advantageous result being due to the fact that the area ofthe floating frame 86 and its flexible connection 87 exposed to thepressure medium is greater than so much of the area of the other side ofthe frame as is exposed to the pressure medium. Whatever the pressure,therefore, the joint is maintained closed. The opposite side section ispositively latched to the first mentioned section, and its rabbetedjoint with I claim:

the fixed frame 85 cannot leak because, while the area against whichpressure acts to cause leakage is the area of the side section boundedby the inner edge of said frame 85, the area against which pressure actsto prevent leakage, acting upon this side section through theintermediary of the latches 89, 92 and 98, is the larger area composedof the area of the first section bounded by the floating frame 86 addedto the area of the floating frame and its flexible connection 87 exposedto the interior of the mold. It is thus practically impossible for anyof the joints to leak.

Differential pressure connections are also provided, between the pipes120 and the side Walls of the bottom section 75 of the flat boardmachine. The spring 117 normally holds the floating pipe 114 outwardlyagainst the elbow 119. Pressure within these pipes tending to break thisjoint by moving floating pipes inwardly against such spring pressure hasonly the area of the float ing pipe at this joint to act against andthis is overcome, as will readily be seen, by the pressure within thebottom section of the -mold acting against the greater area of theflexible diaphragm 115 to force the floating pipe outwardly and maintainthe joint un broken. 7

Another important constructional feature of the flat board machine isthat which admits the same pressure fluid which is admitted to the moldcavity to the chamber in each side section between the walls 82 and 84thereof. The pressure on one side of the wall 82 is therefore exactlycounterbalanced by the pressure on the other side of said wall. There isthus no chance for the huekling of said wall and no necessity formassive bracing or other heavy constructions for the purpose of makingthe mold walls strong enough to withstand the fluid pressure introducedinto the mold. When pulp is admitted into the mold cavity through thepipe 76 it is also free to flow through the pipes 114, 119 and 120 into"the cavities behind the perforated walls of the mold; and when the pulpis withdrawn from the mold cavity through the discharge pipe 78 the pulpin these side cavities is also withdrawn; and

-'when drying fluidis introduced through the pipe 35 into the mold italso enters into these side cavities. Even though air or pulp or otherfluid may be trapped within these side cavities when other fluid isadmitted to the balancing effect is a matter of pressure and not ofpressure medium;

1. The process of molding pulp articles which comprises depositing pulpupon the reticulated wall of a mold until sufficient deposit has beenmade, by introducing pulp liquor under pressure into a mold having suchwall and removing the water which has 3. The process of molding pulparticles I which comprises depositing pulp upon the reticulated wall ofa mold until sufiicient deposit has been made, by introducing pulpliquorunder pressure into a mold having such wall and removing the water whichhas passed through said wall, removing the undeposited pulp and itsliquor substantiall without permitting further deposit, simu taneouslytherewith introducing air under pressure until all the pulp liquor hasbeen removed and then introducing superheated steam under pressure.

4. The process of molding pulp articles which comprises introducingpulp-liquor upwardly into a mold having a reticulated Wall until asuflicient pulp deposit has formed upon said wall, and then suddenlydischarging the undeposited pulp and its liquor through said opening.

5. The process of molding pulp articles which comprises introducingpulp-liquor upwardly into a mold having a reticulated wall until asufficient pulp deposit has formed upon said wall, then suddenlydischarging the undeposited pulp and its liquor through said opening andsimultaneously therewith introducing drying fluid into the mold, wherebypressure upon the deposited pulp is maintained.

6. -The process of molding pul articles which comprises introducingpulpiquor upwardly into a mold having a reticulated wall until asufficient pulp de osit has formed upon said wall, then, sud enlydischarging the undeposited ulp and, its liquor through said opening anslmultaneously therewith mold, and thereafter introducing super-- heatedsteam under pressure. mold, the result will be the same because the .7.The process of molding pulp articles which comprises introducingpulp-liquor under pressure upwardly into a mold having a reticulatedwalluntil a sufiicient-pulp deposit has formed upon said wall,,whereb vintroducing air under pressure. into the an upward current is producedduring deposition preventing the settling ofthe heavier particles ofsaid pulp-liquornpon the mold bottom and causing whatever of such heavypartidles are deposited to be distributed throughout the area ofdeposition, and then suddenly discharging the undeposited pulp and itsliquor downwardly through an opening in said mold bottom.

8. The process of molding pulp articles which comprises introducingpulp-liquor under pressure upwardly into a mold having a reticulatedwall until a suflicient pulp deposit has formed on said wall, whereby anupward current is produced during deposition preventing the settling ofthe heavier particles of said pulp-liquor upon the mold bottom andcausing whatever of such heavy particles are deposited to be distributedthroughout the area of deposition, then suddenly discharging theundeposited pulp and its liquor downwardly through an opening in saidmold bottom and. simultaneously therewith introducing drying fluid underpressure into'the mold.

9. The process of molding pulp articles which comprises introducingpulp-liquor under pressure upwardly into a mold having a reticulatedwall until a suflicient pulp deposit has formed on said wall, whereby anupward current is produced during deposition preventing the settling ofthe heavier particles of said pulp-liquor upon the mold bottom andcausing whatever of such heavy particles are deposited to be[distributed throughout the area of deposition, then suddenlydischarging the undeposited pulp and its liquor downwardly through anopening in said mold bottom, simultaneously introducing air underpressure into the mold until all the said undeposited ulp and its liquorhas been discharged and then introducing superheated steam underpressure into the mold.

10. An apparatus for molding pulp articles, comprising a pulp-liquorcontainer, a mold having a reticulated wall, a valved connection betweensaid container and the bottom portion of said mold forconductingpulp-liquor from said container to said mold, a valved drainage pipeleading from the bottom portion of said mold and a drying fluid pipeleading into said mold.

11. An apparatus for molding pulp articles, comprising a pulp-liquorcontainer, a mold having a reticulated wall, avalved connection betweensaid container and the bottom portion of said mold for conductinpulp-liquor from said container to sai mold, a valved drainage pipeleading from the bottom portion of said mold and a drying fluid pipeleading into said connection at a point below said mold.

12. An apparatus for molding pulp articles, comprising a mold having areticulated wall, and an opening in the bottom thereof, controlled meansfor introducing pulp-liquor into said mold through said opening andcontrolled means for draining said mold through said opening.

13. An apparatus for molding pulp articles, comprising a mold having areticulated wall, and an openin in the bottom thereof, controlled meansfor introducing pulpliquor into said mold, said opening, convided with areticulated wall, a chamber below said mold, a connection between saidmold and said chamber, a valved connection between said container andsaid chamber, a valved drainage pipe from said chamber and a valveddrying fluid pipe leading into said chamber.

16. An apparatus for molding hollow pulp articles, comprising a moldhaving a separable top, bottom and side sections, said sections beingprovided with reticulated walls and said bottom section being providedwith an opening, controlled means for introducing pulp-liquor into saidmold through said opening and controlled means for draining said moldthrough said openm %7. An apparatus for molding hollow pulp articles,comprising a mold having separable top, bottom and side sections, saidsections being provided with reticulated walls and said bottom sectionbeing provided with an opening, controlled means for introducingpulp-liquor into said mold through said opening, controlled means fordraining said mold through said opening and controlled means forintroducing a drying fluid into said mold.

13. An apparatus for molding hollow pulp articles, comprising a moldhaving separable top, bottom and side sections, said sections beingprovided with reticulated walls, a motor, a lever system connecting saidmotor with said top section for separating said top section from saidside section, and a connection between said lever system and saidsidesection and operative to separate said side section from said bottomsection after said top section has been separated from said sidesection.

In testimony whereof I have hereunto set my hand.

JULIAN H. RIVERS.

